term <- c(
     "publication",
     "government + class",
     "publication * government + publication * class",
     "alone + class * alone",
     "military + diplomacy",
     "election + legislation",
     "election * publication + legislation * publication"
)
        
f0 <- reformulate(term[1:2], "lss")
f1 <- reformulate(term[1:3], "lss")
f2 <- reformulate(term[1:4], "lss")
f3 <- reformulate(term[1:5], "lss")
f4 <- reformulate(term[1:6], "lss")
f5 <- reformulate(term[1:7], "lss")

f7 <- reformulate(term[c(1)], "alone")
f8 <- reformulate(term[c(1, 5, 6)], "alone")